1. Field of the Invention
This invention relates to a data reproducing method and apparatus, a data transmitting method, a data transmitting system, and a data processing method and apparatus for protecting the copyright of data recorded on a recording medium or transmitted over a transmission medium, and for safeguarding against unauthorized duplication.
2. Description of the Related Art
Recently, with coming into widespread use of digital contents, such as Internet or digital video discs, infringements of the digital contents by unauthorized duplication of the digital contents, frequently give rise to a problem.
For coping with this problem, there has recently been proposed a method of prohibiting unauthorized copying of picture or music data purveyed in a stored state on a recording medium or using a network as a transmission medium by burying the copyright information in the data by watermark processing.
The watermark processing is the processing of burying the information as a noise in a perceptually non-crucial portions present im the picture or music data, that is in the non-redundant portions with respect to the music or the picture. The copyright information, buried in the picture or music data by such watermark processing, can scarcely be removed, while it can be retrieved even after filtering or data compression.
For overcoming the above problem, it has been proposed to bury the watermark processing in picture data etc or to encrypt data being recorded or transmitted to prohibit unauthorised duplication. By encrypting the recorded or transmitted data, unauthorized duplication cannot be made unless the encrypting algorithm is decoded.
FIG. 1 shows a conventional optical disc reproducing device exploiting the above-mentioned watermark processing and encryption.
The conventional optical disc reproducing device 100, shown in FIG. 1, is applied to, for example, a personal computer.
This optical disc reproducing device 100 includes an optical disc drive 101, a data processing device 102for doing data processing on picture data etc read out from the optical disc drive 101, and a transmission line 103 for interconnecting the optical disc drive 101 and the data processing device 102.
In a data area of an optical disc D is recorded picture data on moving or still pictures or speech data on music or speech. These data are previously compressed in accordance with the MPEG system. On the picture data, the copyright information is superimposed by the above-mentioned watermark processing.
The copyright information, superimposed on the picture data, may be exemplified by the following copyright control information:
That is, there are superimposed on the picture data xe2x80x9ccopy freexe2x80x9d, specifying that picture or music data recorded on the recording medium or transmitted can be copied, xe2x80x9cone copyxe2x80x9d, specifying that only one copying operation is possible, xe2x80x9cno more copyxe2x80x9d specifying that data has been copied from the above xe2x80x9cone copyxe2x80x9d data, or xe2x80x9cnever copyxe2x80x9d specifying that copying cannot be permitted. The reproducing device or the recording device, which has detected this copyright control information, limits reproduction or recording on the picture or music data.
The compressed picture data or compressed speech data, recorded on this optical disc D, is encrypted by a predetermined encrypting key.
On the optical disc D, there is recorded the media type information of this optical disc D, along with the above-mentioned picture data or audio data. This media type information is the information specifying whether the optical disc is the read-only ROM disc or a recordable RAM disc.
From this optical disc D, the above media type information as well as the compressed picture or audio data is read out by the optical disc drive 101.
The optical disc drive 101 sends the read-out compressed picture data, compressed speech data and the media type information over the transmission line 103 to the data processing device 102. The data transmitted on the transmission line 103 is transmitted after being encrypted by the so-called contents scramble system (CSS).
If the present optical disc reproducing device 100 is applied to, for example, a personal computer, the transmission line 103 is connected by the bus line.
The data processing device 102 includes a CSS decoder 104, an MPEG decoder 105, a media type decoder 106, watermark (WM) detection/re-encoding unit 107, an output controller 108, and switches 111, 112.
The data processing device 102 is enclosed in, for example, a data card etc loaded on a personal computer.
The CSS decoder 104 is fed with the compressed picture or audio data and the media type information, transmitted in the encrypted form, and executes decryption using a predetermined encryption key. If decryption is not made using the correct decryption key, the ensuing processing cannot be effectuated. If decryption is done using the correct encryption key, this CSS decoder 104 sends picture data and audio data to the MPEG decoder 105, while sending the media type information to the media type decoder 106.
The MPEG decoder 105 expands the compressed picture and speech data. The expanded picture data is sent to the watermark (WM) detection/re-encoding unit 107, while the expanded speech data is outputted via switch 111 to outside.
The media type decoder 106 decodes the media type information sent from the CSS decoder 104 to detect the information on whether the optical disc D reproduced by the optical disc drive 101 is a ROM disc or a RAM disc, and sends the detected information to the output controller 108.
The watermark (WM) detection/re-encoding unit 107 detects the copyright control information, superimposed on the picture data by watermark processing. The detected copyright control information is xe2x80x9ccopy freexe2x80x9d, xe2x80x9cone copyxe2x80x9d, xe2x80x9cno more copyxe2x80x9d or xe2x80x9cnever copyxe2x80x9d, as described above. The watermark (WM) detection/re-encoding unit 107 sends the detected copyright control information to the output controller 108. If, as a result of detection of the copyright control information, the watermark (WM) detection/re-encoding unit 107 has detected xe2x80x9cone copyxe2x80x9d, it re-encodes the copyright control information superimposed on the picture data by watermark processing to change the copyright control information to xe2x80x9cno more copyxe2x80x9d and outputs the result to outside via switch 112. If, as a result of detection of the copyright control information, the watermark (WM) detection/re-encoding unit 107 has detected the information other than xe2x80x9cone copyxe2x80x9d, it outputs the detected result to outside via switch 112 without performing the re-encoding.
The output controller 108 performs on/off control of the switch 111 and the switch 112, based on the information sent from the media type decoder 106 and the watermark (WM) detection/re-encoding unit 107. Specifically, if the optical disc D is the ROM disc and the copyright control information is xe2x80x9cno more copyxe2x80x9d, and if the optical disc D is the RAM disc and the copyright control information is xe2x80x9cone copyxe2x80x9d, the output controller 108 assumes that data recorded on the optical disc D has been duplicated illicitly, and accordingly controls the switches 111, 112 to off states.
In the conventional optical disc reproducing device 100, as described above, it is possible to encrypt data transmitted between the optical disc drive 101 and the data processing device 102 to prevent unauthorized duplication and to manage control for halting the reproduction of the illicitly duplicated optical disc D using the copyright control information.
In the above-described conventional optical disc reproducing device 100, the processing of superimposing the copyright control information by watermark processing is performed on base-band picture data prior to MPEG encoding. There are occasions, however, wherein the copyright control information is superposed on an elementary stream prior to MPEG encoding. In such case, the data processing device 102 of the optical disc reproducing device 100 is configured so that the watermark (WM) detection/re-encoding unit 107 detects the copyright control information based on the compressed picture data prior to MPEG decoding and the switch 111 is provided between the CSS decoder 104 and the MPEG decoder 105.
It is feared that an unauthorized reproducing device 202 shown in FIG. 3 is provided in the above-described conventional optical disc reproducing device 100. This unauthorized reproducing device 202 acquires input signals from the transmission line 103 between the optical disc drive 101 and the data processing device 102 to effect decryption by an illicitly prepared CSS decoder 204. An MPEG decoder 205 expands picture data obtained from this illicitly prepared CSS decoder 204 to output video and audio data.
That is, in the conventional optical disc reproducing device 100, picture data, speech data and media type information are transmitted after encryption by a sole algorithm. Thus, unauthorized duplication occurs on decoding this sole algorithm.
In consideration that the unauthorized reproducing device 202 is fabricated by decoding the sole encrypting algorithm, a data transmission system with higher security has been a desideratum.
It is therefore an object of the present invention to provide a data reproducing method and apparatus, a data transmitting system, a data transmitting method and a data processing method and apparatus having high security against unauthorized duplication of transmitted or recorded data.
In one aspect, the present invention provides a data reproducing apparatus including reproducing means for reproducing data recorded on a recording medium, first encryption means for performing first encryption processing on the data reproduced by the reproducing means, second encryption means for performing second encryption processing different from the first encryption processing on at least control data concerning copyright control processing of the data reproduced by the reproducing means and transmission means for transmitting the data encrypted by the first encryption means and the second encryption means.
This data reproducing apparatus performs different encoding processing on control data.
In another aspect, the present invention provides a data reproducing apparatus including reproducing means for reproducing data recorded on a recording medium;
encryption means for encrypting the data reproduced by the reproducing means and control data relevant at least to copyright control processing of the data, transmission means for transmitting data encrypted by the encrypting means to an external signal processing device, reception means for receiving playback control data transmitted from the external signal processing device, the playback control data being the data transmitted by the transmission means encrypted in a manner different from the encrypting by the encrypting means and processed with copyright control processing, decrypting means for doing decrypting matched to encrypting of the playback control data received by the reception means, and control means for controlling the playback processing of the reproducing means based on the playback control data decrypted by the decrypting means.
This data reproducing apparatus also performs different encoding processing on control data.
In a further aspect, the present invention provides a data processing apparatus including reception means for receiving data processed with first encrypting processing and control data at least relevant to copyright control processing of the data and which is encrypted by second encrypting processing different from the first encrypting processing, the data and the control data being transmitted from an external device, first decrypting means for doing first decrypting processing, matched to the first encrypting processing, on the data received by the reception means, second decrypting means for doing second decrypting processing, matched to the second encrypting processing, on the data received by the reception means, outputting means for outputting data decrypted by the first decrypting means, and control means for doing copyright control processing of the data outputted by the outputting means, based on at least the control data decrypted by the second decrypting means, for controlling outputting processing of the outputting means.
This data processing apparatus performs different encoding processing on control data.
In a further aspect, the present invention provides a data processing apparatus including reception means for receiving data and control data at least relevant to copyright control processing of the data, the data and the control data being encrypted and transmitted in this encrypted form from an external device, decrypting means for performing matched decrypting processing on the data and the control data received by the reception means, outputting means for outputting data decrypted by the decrypting means, control means for doing copyright control processing of the data outputted by the outputting means, based on at least the control data decrypted by the decrypting means, for generating transmission control data controlling transmission processing of the data transmitted from the external device, encrypting means for performing encrypting processing on the transmission control data generated by the control means, the encrypting processing being different from that on the data and control data received by the reception means and transmitting means for transmitting the transmission control data encrypted by the encrypting means to the external device.
This data processing apparatus performs different encoding processing on control data.
In a further aspect, the present invention provides a data transmission system including a data reproducing apparatus and a data processing apparatus, in which data reproduced from a recording medium by the data reproducing apparatus is transmitted to the data processing apparatus, the transmitted data is processed in a predetermined manner by the data processing apparatus and in which the processed data is outputted,. The data reproducing apparatus includes reproducing means for reproducing data recorded on a recording medium, first encryption means for performing first encryption processing on the data reproduced by the reproducing means, second encryption means for performing second encryption processing different from the first encryption processing on at least control data concerning copyright control processing of the data reproduced by the reproducing means, and transmission means for transmitting the data encrypted by the first encryption means and the second encryption means. The data processing apparatus includes reception means for receiving data processed with first encrypting processing and control data at least relevant to copyright control processing of the data and which is encrypted by second encrypting processing different from the first encrypting processing, the data and the control data being transmitted from an external device, first decrypting means for doing first decrypting processing, matched to the first encrypting processing, on the data received by the reception means, second decrypting means for doing second decrypting processing, matched to the second encrypting processing, on the data received by the reception means, outputting means for outputting data decrypted by the first decrypting means, and control means for doing copyright control processing of the data outputted by the outputting means, based on at least the control data decrypted by the second decrypting means, for controlling outputting processing of the outputting means.
This data transmission system performs different encoding processing on control data.
In a further aspect, the present invention provides a data transmission system including a data reproducing apparatus and a data processing apparatus. The data reproducing apparatus includes reproducing means for reproducing data recorded on a recording medium, including encryption means for encrypting the data reproduced by the reproducing means and control data of the data relevant at least to copyright control processing, transmission means for transmitting data encrypted by the encrypting means to an external signal processing device, reception means for receiving playback control data transmitted from the signal processing device, the playback control data being the data transmitted by the transmission means, the transmitted data being processed with copyright control processing, decrypting means for doing decrypting matched to encrypting of the playback control data received by the reception means, and control means for controlling the playback processing of the reproducing means based on the playback control data decrypted by the decrypting means. The data processing device includes reception means for receiving data and control data at least relevant to copyright control processing of the data, the data and the control data being encrypted and transmitted in this encrypted form from an external device, decrypting means for performing matched decrypting processing on the data and the control data received by the reception means, outputting means for outputting data decrypted by the decrypting means, control means for doing copyright control processing of the data outputted by the outputting means, based on at least the control data decrypted by the decrypting means, for generating transmission control data controlling the transmission processing of the data transmitted from the external device, encrypting means for performing encrypting processing on the transmission control data generated by the control means, the encrypting processing being different from that on the data and control data received by the reception means, and transmitting means for transmitting the transmission control data encrypted by the encrypting means to the external device.
This data transmission system performs different encryption processing on control data.
The data reproducing method according to the present invention reproduces data recorded on the recording medium, performs first encryption processing on the reproduced data, while performing second encryption processing different from the first encryption processing and transmitting the encrypted data and control data.
This data reproducing method performs different encryption processing on control data.
In a further aspect, the present invention provides a data reproducing method including reproducing data recorded a recording medium, performing first encryption processing on the reproduced data, performing second encryption processing, different from the first encryption processing, on at least control data for copyright control processing of the reproduced data, and transmitting the encrypted data and control data.
This data reproducing method similarly performs different encryption processing on control data.
In a further aspect, the present invention provides a data processing method including receiving data subjected to first encryption processing and at least control data of the data subjected to second encryption processing different from the first encryption processing, the data and the control data being subsequently transmitted from an external device, performing first decryption processing matched to the first encryption processing on the received data, performing second decryption processing matched to the second encryption processing on the received control data, performing at least copyright control processing based on control data subjected to the second decryption processing to control output processing.
This data processing method similarly performs different encryption processing on control data.
In a further aspect, the present invention provides a data processing method including receiving data and at least its control data relevant to copyright control processing, the data and the control data being encrypted and transmitted in this encrypted form from an external device, performing matched decryption processing on the received data and control data, outputting decrypted data, performing copyright control processing on the outputted data, based at least on the decrypted control data, to generate transmission control data controlling transmission of data from the external device, performing encryption processing different from that performed on the received data and control data on the generated transmission control data, and transmitting the encrypted transmission control data to the external device.
This data processing method similarly performs different encryption processing on control data.
In a further aspect, the present invention provides a data transmission method in which a transmitting side transmits data reproduced from a recording medium via a transmission medium and in which a reception side performs pre-set processing on transmitted data to output the processed data, wherein the transmitting side reproduces the data recorded on the recording medium, processes the reproduced data with first encryption, processes control data at least relevant to copyright control processing of the data with second encryption different from the first encryption, and transmits encrypted data and control data over a transmission medium, with the reception side receiving the transmitted data and control data, performing first decryption processing matched to the first decryption processing on the received data, and performing second decryption processing matched to the second decryption processing on the received control data. The decrypted data is outputted, and copyright control processing for the outputted data is performed based on at least the control data subjected to the second decryption processing.
This data transmitting method performs different encryption processing on control data.
In yet another aspect, the present invention provides a data transmission method in which a transmitting side transmits data reproduced from a recording medium via a transmission medium and in which a reception side performs pre-set processing on transmitted data to output the processed data, wherein the transmitting side reproduces the data recorded on the recording medium, processes the reproduced data and at least control data of the reproduced data relevant to copyright control processing with encryption, transmits the encrypted data and control data over a transmission medium to the reception side, receives the playback control data encrypted and transmitted in this encrypted form from the reception side, performs decryption processing matched to encryption processing of the received playback control data, and controls playback processing based on the decrypted playback control data sent from the reception side, and wherein the reception side receives the transmitted data and the control data, performs matched decryption processing on the received data and control data, outputs the decrypted data, performs copyright control processing of the outputted data based on at least the decrypted control data, generates transmission control data controlling the transmission of data from the transmitting side, performs decryption processing different from that performed on the received data and control data on the generated transmission control data and transmits the encrypted transmission control data to the transmitting side.
In the data reproducing apparatus, data processing apparatus, data transmitting system, data reproducing method, data processing method, and data transmitting method and apparatus, data and control data therefor are transmitted, while the control data is encrypted in a different manner from the data. This raises security with respect to unauthorized duplication.